How to reset HTC Desire to factory default using phone buttons
* With the phone turned off, press and hold the VOLUME DOWN button, and then briefly press the POWER button.
* Wait for the screen with the 3 Android images to appear, and then release the VOLUME DOWN button.
* Press VOLUME DOWN to select CLEAR STORAGE, and then press POWER.
* When asked to confirm, press VOLUME UP.How to recalibrate G-sensor
Recalibrate the screen if you feel that the screen orientation does not respond properly to the way you hold the phone.
* Press HOME > MENU, then tap Settings > Sound & display.
* Scroll down the screen, and then tap G-Sensor calibration.
* Place the phone on a flat and level surface, and then tap Calibrate.
* After the recalibration process, tap OK.

How to use HTC Desire as a modem (tethering)
* Make sure HTC Sync is installed.
* Make sure your phone’s data connection is turned on.
* Connect the phone to the computer using the provided USB cable.
* On the Connect to PC screen, select Internet sharing, and then tap Done.
* When you are using your phone as a modem, the USB mass storage feature is disabled, and you are also not able to use HTC Sync.HTC Desire User GuideDownload HTC Desire Quick Start Guide Download HTC Desire User Manual